#include "brw_context.h"
#include "intel_screen.h"
+#include "intel_batchbuffer.h"
#include "intel_blit.h"
#include "intel_buffers.h"
#include "intel_fbo.h"
#include "intel_mipmap_tree.h"
#include "intel_pixel.h"
#include "intel_buffer_objects.h"
+#include "intel_tiled_memcpy.h"
#define FILE_DEBUG_FLAG DEBUG_PIXEL
+/**
+ * \brief A fast path for glReadPixels
+ *
+ * This fast path is taken when the source format is BGRA, RGBA,
+ * A or L and when the texture memory is X- or Y-tiled. It downloads
+ * the source data by directly mapping the memory without a GTT fence.
+ * This then needs to be de-tiled on the CPU before presenting the data to
+ * the user in the linear fasion.
+ *
+ * This is a performance win over the conventional texture download path.
+ * In the conventional texture download path, the texture is either mapped
+ * through the GTT or copied to a linear buffer with the blitter before
+ * handing off to a software path. This allows us to avoid round-tripping
+ * through the GPU (in the case where we would be blitting) and do only a
+ * single copy operation.
+ */
+static bool
+intel_readpixels_tiled_memcpy(struct gl_context * ctx,
+ GLint xoffset, GLint yoffset,
+ GLsizei width, GLsizei height,
+ GLenum format, GLenum type,
+ GLvoid * pixels,
+ const struct gl_pixelstore_attrib *pack)
+{
+ struct brw_context *brw = brw_context(ctx);
+ struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
+
+ /* This path supports reading from color buffers only */
+ if (rb == NULL)
+ return false;
+
+ struct intel_renderbuffer *irb = intel_renderbuffer(rb);
+ int dst_pitch;
+
+ /* The miptree's buffer. */
+ drm_intel_bo *bo;
+
+ int error = 0;
+
+ uint32_t cpp;
+ mem_copy_fn mem_copy = NULL;
+
+ /* This fastpath is restricted to specific renderbuffer types:
+ * a 2D BGRA, RGBA, L8 or A8 texture. It could be generalized to support
+ * more types.
+ */
+ if (!brw->has_llc ||
+ !(type == GL_UNSIGNED_BYTE || type == GL_UNSIGNED_INT_8_8_8_8_REV) ||
+ pixels == NULL ||
+ _mesa_is_bufferobj(pack->BufferObj) ||
+ pack->Alignment > 4 ||
+ pack->SkipPixels > 0 ||
+ pack->SkipRows > 0 ||
+ (pack->RowLength != 0 && pack->RowLength != width) ||
+ pack->SwapBytes ||
+ pack->LsbFirst ||
+ pack->Invert)
+ return false;
+
+ /* This renderbuffer can come from a texture. In this case, we impose
+ * some of the same restrictions we have for textures and adjust for
+ * miplevels.
+ */
+ if (rb->TexImage) {
+ if (rb->TexImage->TexObject->Target != GL_TEXTURE_2D &&
+ rb->TexImage->TexObject->Target != GL_TEXTURE_RECTANGLE)
+ return false;
+
+ int level = rb->TexImage->Level + rb->TexImage->TexObject->MinLevel;
+
+ /* Adjust x and y offset based on miplevel */
+ xoffset += irb->mt->level[level].level_x;
+ yoffset += irb->mt->level[level].level_y;
+ }
+
+ /* It is possible that the renderbuffer (or underlying texture) is
+ * multisampled. Since ReadPixels from a multisampled buffer requires a
+ * multisample resolve, we can't handle this here
+ */
+ if (rb->NumSamples > 1)
+ return false;
+
+ /* We can't handle copying from RGBX or BGRX because the tiled_memcpy
+ * function doesn't set the last channel to 1.
+ */
+ if (rb->Format == MESA_FORMAT_B8G8R8X8_UNORM ||
+ rb->Format == MESA_FORMAT_R8G8B8X8_UNORM)
+ return false;
+
+ if (!intel_get_memcpy(rb->Format, format, type, &mem_copy, &cpp,
+ INTEL_DOWNLOAD))
+ return false;
+
+ if (!irb->mt ||
+ (irb->mt->tiling != I915_TILING_X &&
+ irb->mt->tiling != I915_TILING_Y)) {
+ /* The algorithm is written only for X- or Y-tiled memory. */
+ return false;
+ }
+
+ /* Since we are going to read raw data to the miptree, we need to resolve
+ * any pending fast color clears before we start.
+ */
+ intel_miptree_resolve_color(brw, irb->mt);
+
+ bo = irb->mt->bo;
+
+ if (drm_intel_bo_references(brw->batch.bo, bo)) {
+ perf_debug("Flushing before mapping a referenced bo.\n");
+ intel_batchbuffer_flush(brw);
+ }
+
+ error = brw_bo_map(brw, bo, false /* write enable */, "miptree");
+ if (error) {
+ DBG("%s: failed to map bo\n", __func__);
+ return false;
+ }
+
+ dst_pitch = _mesa_image_row_stride(pack, width, format, type);
+
+ /* For a window-system renderbuffer, the buffer is actually flipped
+ * vertically, so we need to handle that. Since the detiling function
+ * can only really work in the forwards direction, we have to be a
+ * little creative. First, we compute the Y-offset of the first row of
+ * the renderbuffer (in renderbuffer coordinates). We then match that
+ * with the last row of the client's data. Finally, we give
+ * tiled_to_linear a negative pitch so that it walks through the
+ * client's data backwards as it walks through the renderbufer forwards.
+ */
+ if (rb->Name == 0) {
+ yoffset = rb->Height - yoffset - height;
+ pixels += (ptrdiff_t) (height - 1) * dst_pitch;
+ dst_pitch = -dst_pitch;
+ }
+
+ /* We postponed printing this message until having committed to executing
+ * the function.
+ */
+ DBG("%s: x,y=(%d,%d) (w,h)=(%d,%d) format=0x%x type=0x%x "
+ "mesa_format=0x%x tiling=%d "
+ "pack=(alignment=%d row_length=%d skip_pixels=%d skip_rows=%d)\n",
+ __func__, xoffset, yoffset, width, height,
+ format, type, rb->Format, irb->mt->tiling,
+ pack->Alignment, pack->RowLength, pack->SkipPixels,
+ pack->SkipRows);
+
+ tiled_to_linear(
+ xoffset * cpp, (xoffset + width) * cpp,
+ yoffset, yoffset + height,
+ pixels - (ptrdiff_t) yoffset * dst_pitch - (ptrdiff_t) xoffset * cpp,
+ bo->virtual,
+ dst_pitch, irb->mt->pitch,
+ brw->has_swizzling,
+ irb->mt->tiling,
+ mem_copy
+ );
+
+ drm_intel_bo_unmap(bo);
+ return true;
+}
+
void
intelReadPixels(struct gl_context * ctx,
GLint x, GLint y, GLsizei width, GLsizei height,
GLenum format, GLenum type,
const struct gl_pixelstore_attrib *pack, GLvoid * pixels)
{
+ bool ok;
+
struct brw_context *brw = brw_context(ctx);
bool dirty;
- DBG("%s\n", __FUNCTION__);
+ DBG("%s\n", __func__);
if (_mesa_is_bufferobj(pack->BufferObj)) {
if (_mesa_meta_pbo_GetTexSubImage(ctx, 2, NULL, x, y, 0, width, height, 1,
- format, type, pixels, pack))
+ format, type, pixels, pack)) {
+ /* _mesa_meta_pbo_GetTexSubImage() implements PBO transfers by
+ * binding the user-provided BO as a fake framebuffer and rendering
+ * to it. This breaks the invariant of the GL that nothing is able
+ * to render to a BO, causing nondeterministic corruption issues
+ * because the render cache is not coherent with a number of other
+ * caches that the BO could potentially be bound to afterwards.
+ *
+ * This could be solved in the same way that we guarantee texture
+ * coherency after a texture is attached to a framebuffer and
+ * rendered to, but that would involve checking *all* BOs bound to
+ * the pipeline for the case we need to emit a cache flush due to
+ * previous rendering to any of them -- Including vertex, index,
+ * uniform, atomic counter, shader image, transform feedback,
+ * indirect draw buffers, etc.
+ *
+ * That would increase the per-draw call overhead even though it's
+ * very unlikely that any of the BOs bound to the pipeline has been
+ * rendered to via a PBO at any point, so it seems better to just
+ * flush here unconditionally.
+ */
+ intel_batchbuffer_emit_mi_flush(brw);
return;
+ }
- perf_debug("%s: fallback to CPU mapping in PBO case\n", __FUNCTION__);
+ perf_debug("%s: fallback to CPU mapping in PBO case\n", __func__);
}
+ ok = intel_readpixels_tiled_memcpy(ctx, x, y, width, height,
+ format, type, pixels, pack);
+ if(ok)
+ return;
+
/* glReadPixels() wont dirty the front buffer, so reset the dirty
* flag after calling intel_prepare_render(). */
dirty = brw->front_buffer_dirty;
projects / mesa.git / blobdiff